Concrete pipes and other such bodies



1966 G. R. GOFFIN ETAL CONCRETE PIPES AND OTHER SUCH BODIES Filed Nov. 23, 1962 CONCRETE I 7 cmemmous MOETAR LAYER PLASTIC 1: 719 l f f r ll I l l -H PH 1 1a In E 4 a V 4 /Vl/7I 19 a 5 10 n 7 Fog! 1 INVENTORS GOFFIN CLIFFORD A BAKE-R N C'ORNWELL to be encountered in actual use.

United States Patent Ofi ice 3,251,720 Patented May 17, 1966 3,251,720 CONCRETE PIPES AND OTHER SUCH BODIES George Robert Goflin, Kew, Victoria, Clifford Aubrey Baker, Clayton, Victoria, and John Shawcross Comwell, Box Hill, Victoria, Australia, assignors to Humes Limited, Melbourne, Victoria, Australia, a company of Victoria Filed Nov. 23, 1962, Ser. No. 239,696 Claims priority, application Australia, Nov. 30, 1961, 11,914/61; Feb. 12, 1962, 14,269/62 12 Claims. (Cl. 156-73) pipe, a suitable vibrator is attached to a metal or timber This invention relates to concrete pipes and other such bodies, more particularly to methods of, and means for, sealing the internal surfaces, or parts thereof, so as to render them fluid tight and impervious, or highly resistant to chemical or other deleterious influences likely It also relates to similar sealing of the top or outer surface of concrete articles or structures such as slabs and floors, where this surface is formed without the aid of a mould.

In connection with concrete pipes manufactured with the aid of an internal mould or core it has already been proposed to utilise plasticed polyvinyl chloride sheet or foil provided on one surface with ribs, protuberances or like formations (hereinafter referred to as projections) of T, L, diamond or other shape, which become embedded in the inner surface layer of the pipe and thus retain the foil as a kind of skin after the pipe has set.

It has also been proposed, in the case of the internal surface of concrete pipes and other such bodies, and other concrete surfaces formed without the aid of a mould or core, to seal'the concrete surface with a foil (plasticised polyvinyl chloride, rigid polyvinyl chloride, polyethylene, neoprene or any other plastic or rubber type larly applicable, although not limited, to pipes made by the centrifugal or spinning process and which are relatively dense or hard, and ensuring a most effective and durable bond between the foil and the pipe. The method applies to any foil provided on at least one surface with projections which can become embedded in the concrete surface. The foil can be flexible, semi-rigid or rigid.

The invention also provides simple equipment for carrying the method into eflect.

The first step is to prepare a suitable surface on the concrete. In the case of a spun pipe this can be done either by introducing a suitable quantity of mortar (sand, cement and water, or cement and water) into the pipe and rotating the latter at a suitable speed, or proportioning the concrete usedin manufactrue of the pipe to form the necessary surface after completion of manufacture, or a combination of both methods. In the case of cast concrete, e.g. floors or slabs, wherethe top surface is to be sealed, a suitable surface can usually be formed by appropriate proportioning of the ingredients of the concrete mix, but, if necessary, mortar can be placed on the top of the concrete by hand, by rolling, vibration or any other method. Alternatively any other suitable bonding agent may be incorporated on the surface to be sealed. 4

section which rests on the invert or lower arc of the pipe. As the mould is rotated the vibrating member slides across the foil and sets up what may be termed a combined tamping and rubbing or squeezing action which fluidises the concrete surface and results in the foil projections to be firmly embedded in the surface layer of the pipe. In any event, this ensures effective bonding of the projections. Alternatively, the vibrating member or roller may be shaped to form an arc of the same radius as the pipe, and moved longitudinally through the pipe, firmly embedding the projections. The mould can then be rotated, to bring the next strip of foil under the vibrating screed or roller, and the process repeated until all the foil has been firmly embedded. A similar procedure, where a vibrating screed or roller is advanced across'the surface, embedding the whole or part of'the foil at each pass, may be necessary for concrete surfaces other than pipes. Initial and final alignment of the foil can be made by using clamps.

An alternative procedure for spun pipes also involves the first mentioned step, after which a sheet of theplastic foil, rolled into more or less tubular formation, is in-.

serted into the pipe with the projections of the foil outermost. The pipe is then spun at relatively hi-ghspeed, to cause the centrifugal force generated to imbed the plastic projections into a cementitious mortar layer located on the inner surface of the pipe, while a light roller may be utilised to press the foil against said inner surface of the pipe. In this way also the projections of the foil become embedded in the inner surface of the pipe, and form a strong and lasting bond.

An embodiment of the invention will now be described in more detail by way of example, with reference to the accompanying drawings, in which FIGURE 1 is sectional view in side elevation of a spun concrete pipe during the process of placing a flexible plastic foil, with projections, in the pipe. FIGURE 2 is an end View at the same stage of the process. FIGURE 3 is an enlarged fragmentary sectional view through a completed pipe.

The preparation and manufacture of the lined concrete pipe is carried out in the following manner:

Using a conventional mould 1 and mould ends 2 a concrete pipe is spun in the normal manner. The concrete mix used is so proportioned that the final pipe consists of a basic concrete layer 3 with a cementitious mounted on a drum 15, with the projections outermost.

This drum is supported independently of the pipe from the base plate 5 by stands 16, so arranged that the roll of foil is in the uppermost section of the pipe, but not in contact with the concrete. A length of-the foil is then unrolled and brought into contact with the concrete surface over an arc of about 120, and extending for a suitable distance past the invert of the pipe. The foil is then carefully aligned so that the longitudinal axis of the coil is parallel to the longitudinal axis of the pipe, and clamped in that position by G-clamps 17, bearing against the plastic foil and mould ends 2.

A vibrating screed is then introduced into the pipe, parallel to its length, at the invert. This screed consists of a vibrator support bar 19, from which hang one or more curved vibrating shoes 18, each with one or more vibrators 21 attached. These shoes 18 are suspended by hangers 20 which allow freedom of movement in a vertical direction. The vibrator power supply leads 23 are attached to the support bar 19. The vibrating screed is located and held in position by support 22, and the vibrator power supply leads are then connected to the power supply (not shown on drawings).

The vibrators 21 are then activated, and at the same time the pipe is slowly rotated by turning handle or by power 9 in such a direction as to advance the vibrating screed towards the nearer end of the foil. The application of vibration then embeds the foil projections into the concrete surface. When the leading edge of the foil has been reached, the direction of rotation of handle 9 is reversed, and, if the lining is not to cover the whole circumference of the pipe, a clamp 25 may be placed over the whole, length of the leading edge to hold it in place. Clamps 17 are removed at this stage, and the rotation is continued until the whole of the foil has been embedded. If the whole pipe circumference is not lined, a furtherclamp similar to 25 is placed on the other edge of the foil. One or more further rotations of the pipe, in opposite directions, may be required. When the plastic foil is fully embedded the vibrators are stopped, the vibrating screed and drum 15 are removed, and the lined pipe is cured as in normal practice. With partial linings, some hand smoothing of the surface of the unlined pipe may be necessary.

For complete or 360 lining concrete pipes and other such bodies, one of the opposite longitudinal extending edge portions of the foil may be devoid of the projections to an extent sufiiciently to provide for a relatively flat overlap of the foil. The overlapped portions may be heat fused together, or joined by any other method. Alternatively, if it is desired to avoid such overlapping,

then the edges of the foil may be abutted and covered,

with a thin strip of foil which can be secured to the abutted edge portions in any suitable way, as, for in-- stance, by being welded with the aid of a heated member such as a tube through which hot air is passed.

Either or both of the other or transverse edgesof-the plastic foil may also be devoid of projections, and project slightly beyond the ends of the pipe as seen in FIG. 1, thus forming overhanging flaps which may be joined together as above to provide continuous sealing from one concrete pipe or product to the next, where these products are to be formed end to end or side by side.

The method for lining spun concrete pipes with a rigid or semi-rigid plastic is similar to the above, except that I the plastic foil is not introduced into the pipe coiled on the drum 15, but is preformed to the correct diameter (or slightly oversize), slit and held in a slightly collapsed position. It is then inserted into the pipe and released to contact the concrete surface with the projections outermost. For full circumference lining, there is still some foil overlap at this stage,'ar1d this overlap must be held clear while vibrating in that region.

According to an alternative process, the vibrating screed is replaced by a roller, which may be rubber coated. This roller is forced down onto the foil and, as the pipe is slowly rotated, the pressure causes full embedment of the foil projections. Clamps 17 and 25 may be employed in the same manner as before described.

According to another alternative process where the foil is applied by centrifugal force, the foil may be placed in the pipe as described for rigid foil above, and the pipe is then rotated at high speed. Centrifugal forces, assisted by light roller pressure causes the ribs to become embedded in the concrete surface.

For the sealing of the top of concrete products where the surface is formed without using a mould, the process is similar. After formation of the necessary concrete surface, the plastic foil is laid, projections downmost, on the surface. A vibrating screed or roller, similar to those used for spun pipes, is placed on the foil, and slowly moved across the surface of the foil.

Having now described our invention, what we claim as new and desire to secure by Letters Patent is:

1. A method of sealing concrete with a plastic foil having projections on one saids, comprising the steps of forming an article of concrete so that it includes a cementitous mortar surface layer of sufficient plasticity to receive the projections of the plastic foil, appling the :foil to the layer with the projections in contact with the layer,

and then applying pressure to the foil so as to force the projections into the layer to be firmly embedded therein when the layer sets.

2. A method as claimed in claim 1, wherein said step of applying projection-embedding pressure is exerted by a vibratory member which is traversed over the foil while vibrating to producea combined tamping, rubbing and squeezing action that fluidises said surface layer and forces the foil projections into the layer.

3. A method as claimed in claim '1 wherein said article of concrete is a hollow body, said step of applying projection-embedding pressure is exerted :on the foil by centrifugal force created by spinning the hollow body with the foil in tubular form therein.

4. A method as claimed in claim ll wherein said article of concrete is a hollow body and said mortar surface layer is the inner surface of the body, said foil being drawn oif a roll extending lengthwise within the hollow body and caused to pass between the inner surface of the body and a roller while rotationg the body, said roller pressing the foil projections into the inner surface layer of the body.

5. A method as claimed in claim 1 wherein said article of concrete is a hollow body and said mortar surface layer is the inner surface of the body, said foil being drawn off a roll extending lengthwise within the upper part of the hollow body and caused to pass between the inner sur- 7. A method as claimed in claim 3 wherein opposite edges of said tubular lining formed by the foil are abutted and covered with a thin strip of foil, and heat is applied to the abutted edge portions of the foil to fuse said strip of foil and abutted edges together; i

8. A method as claimed in claim -5 wherein one ofthe opposite edge portions of the tubular lining formed by the foil is overlapped, and heat is applied to fuse the overlapped edge portion to the other edge portion.

9. A method as claimed in claim 5 wherein opposite edges of the tubular lining formed by the foil are abutted and covered with a thin strip of foil, and heat is applied to fuse the abutted edge portions of the 'foil to said thin strip.

10. Apparatus for sealing the internal surfaces of hollow pipe-like bodies formed of concrete with plastic foil provided on one surface with projections, comprising means for supporting and rotating the hollow body about its axis, means for supporting a roll of the foil lengthwise within the upper part of the body so that the foil can be drawn 01? from the roll, a vibrator device lengthwise within the lower part of the body and having at least one curved shoe between which and the internal surface of the body the toil may be led from said roll, and means for vibrating the vibrator device while rotating the body so as to progressively fluidise the inner surface layer of the rotating body and force the foil projections into said surface layer.

11-1. Apparatus according to claim 10 and including clamps which are applied to retain the foil against the inner surface of the body between said roll and the leading edge of the ioil.

\12. Apparatus according to claim 11 and including additional clamps which are applied to retain the leading edge of the foil to the inner surface of the body.

References Cited by the Examiner UNITED STATES PATENTS 2,633,894 2/1953 Carwile 115673 2,651,148 9/1953 Carwile 15673 2,719,348 10/1955 Desnos 264'270 2,789,934 4/1957 Busbach 15628 7. 2,859,151 11/1958 Usab et al. 156-74 2,887,721 5/1959 Blanchi et a1. =15673 2,961,716 11/1960 Luenberger 156-74 3,002,871 110/ 1961 Tramm et a1. 1 -5673 3,131,104 4/1964 Korn 1567'3 OTHER REFERENCES Modern Plastics, Fabricating With Frictional Heat, R. N. Freres, November 1945, pp. 142444.

EARL M. BERGERT, Primary Examiner.

Examiners. 

1. A METHOD OF SEALING CONCRETE WITH A PLASTIC FOIL HAVING PROJECTIONS ON ONE SAIDS, COMPRISING THE STEPS OF FORMING AN ARTICLE OF CONCRETE SO THAT IT INCLUDES A CEMENTITIOUS MORTAR SURFACE LAYER OF SUFFICIENT PLASTICITY TO RECEIVE THE PROJECTIONS OF THE PLSTIC FOIL, APPLING THE FOIL TO THE LAYER WITH THE PROJECTIONS IN CONTACT WITH THE LAYER, AND THEN APPLYING PRESSURE TO THE FOIL SO AS TO FORCE THE PROJECTION INTO THE LAYER TO BE FIRMLY EMBEDDED THEREIN WHEN THE LAYER SETS.
 10. APPARATUS FOR SEALING THE INTERNAL SURFACES OF HOLLOW PIPE-LIKE BODIES FOMED OF CONCRETE WITH PLASTIC FOIL PROVIDED ON ONE SURFACE WITH PROJECTIONS, COMPRISING MEANS FOR SUPPORTING AND ROTATING THE HOLLOW BODY ABOUT ITS AXIS, MEANS FOR SUPPORTING A ROLL OF THE FOIL LENGTHWISE WITHIN THE UPPER PART OF THE BODY SO THAT THE FOIL 